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Elucidation of Ion Exchange Property of Brown Coals in Relation to Their Higher Order Structure

褐煤离子交换特性与其高阶结构的关系的阐明

基本信息

批准号：
07650914
负责人：
NISHIYAMA Yoshiyuki
金额：
$ 1.41万
依托单位：
TOHOKU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

项目摘要

The present project aims at elucidating the ion exchange property of Australian brown coals, Yallourn and Loy Yang. The property is expected to be heavily dependent of the higher order structure of the coals. The main results obtained are as follows.1. Exchange of transition metal cations is found to proceed only slowly. By pre-exchanging the functional groups of coal with sodium or calcium, the exchange with iron or nickel cations were found to take place rapidly.2. The ability of coals to accept cations is largely suppressed by heat treatment, though the number of the acidic functional groups did not decrease so much. By adding to the exchange solution organic solvents such as acetone, methanol or ethanol, the extents of cation exchange of heat-treated coals were found to be promoted profoundly and the effects seem to correlate with the swelling of the coal.3. The rate of cation exchange is found to vary depending on the cation species and the temperature. The addition of ethanol did not change the rate, but the extent of cation exchange.4. The amount of extracted humic acid by alkali decreased with the temperature of heat treatment, but the exchange with calcium maintained the easiness for extraction from heat treated coals.5. Swelling experiments indicated a reduction in the degree of swelling due to heat-treatment. Exchanged calcium seems to suppress the swelling.6. Selectivity of cation exchange from mixed solutions of cobalt and nickel did not show any preference to a particular cation. Some dependence on pH of the solution was noted for the selectivity from cobalt-magnesium solution. The behavior can be explained on a basis of the radius of the hydrated cations.

本项目旨在阐明澳大利亚褐煤、Yallourn和Loy Yang的离子交换性能。预期该性质严重依赖于煤的高级结构。主要研究结果如下：1.发现过渡金属阳离子的交换仅缓慢进行。用钠或钙对煤的官能团进行预交换，发现与铁或镍阳离子的交换反应进行得很快.煤接受阳离子的能力在很大程度上受到热处理的抑制，虽然酸性官能团的数量没有减少这么多。在交换液中加入丙酮、甲醇或乙醇等有机溶剂，可以显著促进热处理煤的阳离子交换程度，这种作用似乎与煤的溶胀有关.发现阳离子交换的速率根据阳离子种类和温度而变化。乙醇的加入不改变阳离子交换速率，但改变阳离子交换程度.随着热处理温度的升高，碱提取腐殖酸的量减少，但与钙的交换作用保持了热处理煤中腐殖酸的易提取性.溶胀实验表明，由于热处理的溶胀度的减少。交换的钙似乎抑制肿胀。6.从钴和镍的混合溶液的阳离子交换的选择性没有表现出任何偏好，以特定的阳离子。从钴-镁溶液的选择性注意到溶液的pH的一些依赖性。该行为可以根据水合阳离子的半径来解释。